In the electrical power distribution field, electrical circuit breaker panelboards are generally designed to distribute a nominally rated current. However, in applications having non-linear loads, harmonic currents may increase the neutral conductor loading up to 187% of the nominal rating. An accepted method for handling the currents in this condition, is to double the number of neutral conductors. In order to accommodate this increase in the number of neutral conductors, there must be a corresponding increase in the number of terminal lug connectors available at the neutral conductor terminals. However, in most cases, additional space is not available in the panelboard to add more terminal connectors.
Most panelboards have their neutral lug terminal connectors positioned in a two dimensional rectangular flat plane fashion by only utilizing length and width, with depth used as a single plane. Hence, the total number of terminal connectors that can be accommodated with the panelboard is limited. One solution to this problem was to utilize a terminal block connector having wire conductor ports at different elevations. Another solution to the problem was to fasten connector terminal strips to a plate at different elevations. However, the solutions presented in the prior art had the limitations of not allowing the terminal connectors to be interchangeable and prohibited easy access to the wire conductor fasteners after the wire conductors were installed in the connectors. According to the present invention, available panelboard space is efficiently used in terms of its three dimensional parameters, length, width and depth while allowing the terminal connectors to be interchangeable. The present invention increases the number of terminal connectors that can be positioned within the panelboard by maximizing the utilization of the depth dimension within the panelboard. Furthermore, it is desirable to use standard neutral conductor lug bar connectors and provide a means of flexibly arranging the combinations of terminal connector sizes for different ampacity applications while allowing easy access to the wire Fasteners. The neutral lug assembly of the present invention is sized to conduct the potential current loads that occur with non-linear loads and has interchangeable connectors arranged in the form of stair steps to allow termination of conductors at various elevations without obscuring any previous connection.